Here's my choices
1. Sunfish- I understand these are probably widely available in the USA but there is little availability here in Canada (at least my part). You can only get Longears and our local shop has only got them in about once in the last 5 years so I would like to see a bit more availability and maybe more types. they have had requests for them so there is some demand. They are a colorful hardy, interesting fish and it would be great to actually be able to get them.
2.Rosy Bitterling- Very low availability here, only a couple of stores can get them on a seasonal basis and they are pretty expensive. from what I have read on some other sites avilability in many parts of the states isn't great ether So it would be great if more stores carried them.They are another nice, colorful, hardy fish which would probably sell if more widely available.
3.Edible Dormouse-Pretty much no availability in North America at all, very popular pet overseas, easy to care for. Has a pet history dating back to the Roman Empire.
4.Virginia Opossum-Some availability in States, none here.Would appeal to people who work during the day and are home at night (given its nocturnal habits), can be trained to use a litterbox
5. Viscachas- Little availability in North America, kept as a pet in South America. It would be a nice change for people who have already had Rabbits and Chinchillas. Stands the cold better then Chinchillas.A few years ago when stores up here started carrying Degus (another South American mammal) they proved quite popular so they could capitalize on this popularity.
6. Maras and Tuco Tuco- Most of my remarks for the previous hold true though there may be a bit more availability of Maras
7. Patagonia Sierra Finch-No or very little availability. Bright color diverse diet and not at risk in native range (easier to obtain). Would be a nice addition to currently available Finchs.
8. Steppe Lemming- Fairly popular overseas, very limited availability in USA.Fluffy gentle Rodent.
9. Wall Lizards-Limited avilability. Fairly tame, hardy (no heat lamp needed generally)
10. Austral Parakeet-Limited Availability. Colorful, not at risk in native range (easier to bring into trade), popular pet elsewhere.